It would depend on if you're looking for the easy way or the hard way. The best (but most expensive) way is to change pistons. Not something for the faint of heart or wallet.
In the 'good old days' a reasonable increase in compression could also be had by exchanging the head gasket for a thinner version and/or machining (i.e., milling) a few thousandth of an inch (typically .015 to .030) from the cylinder head. In today's world with thin wall castings etc. I wouldn't venture a guess as to whether the "OLD SCHOOL" approach would be safe or effective. Perhaps someone with specific knowledge of the Ztech would care to jump in???
